This application relates to an air machine in which an air-driven turbine drives an air compressor, wherein journal bearings for a central shaft are provided with a dual path cooling.
Air machines are known and include a turbine driving a compressor. Partially compressed air is delivered to the compressor, and the compressor is driven to further compress this air. This compressed air is passed downstream to drive a turbine, with the turbine in turn driving the compressor as the air expands across the turbine. This expanded air is then utilized for a downstream use, such as cabin air for an aircraft.
The known air machines have a shaft which connects the compressor and the turbine. Journal bearings are provided for this shaft. In the past, an air cooling system was provided to pass air between the inner periphery of the journal bearing, and the outer periphery of the shaft.